It is desirable to obtain isolation between two antennas mounted on a metallic aircraft surface, such as when one antenna is transmitting and the other is a receiving antenna. It has been proposed to coat the surface of the aircraft with magnetically loaded elastomeric layers which, although they are thin for a given wave length, are quite heavy and therefore are not practical for long wave lengths in the order of a foot or more. The layer of material is expensive and difficult to fabricate and to install, and most importantly, it is very heavy and bulky if used for long wave lengths, thus adding materially to the weight of the aircraft. Basically, the layer of material consists of magnetic particles imbedded in the elastomer to act as magnetic absorbers to thereby reduce the coupling between the two adjacent antennas.